Rapid dissolving water-soluble polymers

ABSTRACT

WATER-SOLUBLE VINYL ADDITION POLYMERS MAY BE RAPIDLY DISSOLVED IN WATER BY FIRST DISPERSING THESE POLYMERS INTO A WATER-IN-OIL EMULSION AND THEN INVERTING THESE EMULSIONS IN WATER. THE INVERSION OF THE EMULSION RELEASES THE POLYMER INTO WATER AS A SOLUTION.

United States Patent Oflice 3,734,873 Patented May 22, 1973 RAPID DISSOLVING WATER-SOLUBLE POLYMERS Donald R. Anderson, Oswego, and Alvin J. Frisque,

La Grange, Ill., assignors to Nalco Chemical Company, Chicago, Ill. No Drawing. Continuation of application Ser. No.

172,946, Aug. 18, 1971, which is a continuation-inpart of application Ser. No. 92,031, Dec. 15, 1970, now Patent No. 3,624,091. This application Aug. 7,

1972, Ser. No. 278,329

Int. Cl. C08g 47/16, 47/18 US. Cl. 260--29.6 H 13 Claims ABSTRACT OF THE DISCLOSURE Water-soluble vinyl addition polymers may be rapidly dissolved in water by first dispersing these polymers into a water-in-oil emulsion and then inverting these emulsions in water. The inversion of the emulsion releases the polymer into water as a solution.

This is a continuation of copending application Ser. No. 172,946, filed Aug. 18, 1971 and now abandoned; which is a continuation-in-part of application Ser. No. 92,031, filed Dec. 15, 1970-, now US. Patent 3,624,091.

INTRODUCTION Various synthetic and naturally-occurring Water-soluble polymers have been developed which exhibit, in aqueous solution, superior thickening and fiocculating properties. These polymers are being used increasingly in a number of commercial applications such as, for example, in the clarification of aqueous solutions, in papermaking operations, in the treatment of sewage and industrial wastes, as stabilizers for drilling muds, and in the secondary recovery of petroleum by Waterfiooding.

Although these polymers are most often available commercially as powders or as a finely-divided solid, they are most frequently utilized as aqueous solutions. This necessitates that the solid polymer material be dissolved in water. Although the various polymers are more or less soluble in water, difficulty is often experienced in preparing aqueous polymer solutions because of their slow dissolution and because the solid polymer is not readily dispersible in water. Furthermore, dispersion of solid polymers in water is hindered by their tendency to clump or remain as agglomerates on contact with water. Lumps of solid polymer immediately form by the encapsulation of undissolved solids in an outer coating of water-wet polymer which retards the penetration of additional water into the agglomerate. Although many of these lumps are eventually dissolved by continued agitation, it is frequently impractical to agitate the solution for a sufficiently long period to obtain complete dissolution.

THE INVENTION This invention is directed to the discovery that watersoluble vinyl addition polymers and gums may be rapidly dissolved or dispersed in water which comprises the steps of:

(A) first preparing a water-in-oil emulsion which contains dispersed therein finely-divided particles of the water-soluble vinyl addition polymer or gum. This produces what may be termed as polymer-containing emulsion;

(B) the polymer-containing emulsion is then inverted in water whereby the water-soluble vinyl addition polymer or gum is released into the water as a solution.

THE WATER-SOLUBLE VINYL ADDITION POLYMERS These polymers are well-known to the art and have been described in numerous publications and patents. The polymers most commonly used in many industrial applications are acrylamide polymers which include polyacrylamide and its water-soluble copolymeric derivatives such as, for instance, acrylamide-acrylic acid, and acrylamide-acrylic acid salt copolymers which contain from about -5 by weight of acrylamide. Also useful are copolymers of acrylamide with other vinyl monomers such as maleic anhydride, acrylonitrile, styrene and the like. It is preferred in the practice of this invention to use acrylamide polymers which are water-soluble and which contain at least 5% by weight of acrylamide.

Other water-soluble vinyl polymers are described in. detail in the following US. Pats: Nos. 3,418,237, 3,259,- 570 and 3,171,805.

In examining the disclosures of these patents it will be seen that the water-soluble polymers may be either cationic or anionic and, in some instances, the ionic charges are sutficiently slight so that the polymers may be considered as nonionic.

For example, water-soluble polymers and copolymers of allyl, diallyl amines, or dimethylaminoethylmethacrylate are cationic. Polymers such as polyvinyl alcohol are nonionic, and polymers such as polyacrylic acid or polystyrene sulfonates are anionic. All of these polymers may be used in the practice of the invention.

The molecular weight of the polymers described above may vary over a wide range, e.g. 10,000-25,000,000. The invention, however, finds its greatest usefulness in preparing aqueous solutions or dispersions of these polymers and, in particular, acrylamide polymers whose molecular weight are in excess of 1,000,000. Polymers having higher molecular weights are more difiicultly dissolved in water and tend to form extremely viscous solutions at relatively low concentrations. Also, the polymers may be produced by any known methods of conducting polymerization reactions. Thus, solution suspension or emulsion polymerization techniques may be used. The gums are wellknown water-soluble polymers and are described in vol. 10 of the Encyclopedia of Chemical Technology, 2nd edition, Interscience Publishers, 1966.

The invention is capable of producing rapidly aqueous solutions of the water-soluble vinyl addition polymers or gums having concentrations within the range of 0.1 20% by weight. The invention most often finds usefulness when it is desired to form aqueous solutions of polymers having a solution concentration of 0.22.0% by weight.

THE WATER-IN-OIL EMULSIONS The water-in-oil emulsions may be prepared by any number of known techniques. The oils used in preparing these emulsions may be selected from a large group of organic liquids which include liquid hydrocarbons and substituted liquid hydrocarbons.

A preferred group of organic liquids are the hydrocarbon liquids which include both aromatic and aliphatic compounds. Thus, such organic hydrocarbon liquids as benzene, xylene, toluene, mineral oils, kerosenes, naphthas and, in certain instances, petrolatums may be used. A particularly useful oil from the standpoint ofits physi- 3 Cal and chemical properties is the branch-chain isoparafiinic solvent sold by Humble Oil & Refining Company under the trade name "Isopar M." Typical specifications of this narrow-cut isoparafiinic solvent are set forth below in Table I:

TABLE 1 Mini- .\Iaxi Specification properties mum uiuin 'ltx t method Gravity. AII at tin/(30 F. 425. t) 51. ASTM 1) J37. Color, Saybolt 3n ASTM I) 1515. Aniline point, F 185 M 1) till. Sulfur, p.p.ut It) A: l M I) 1206 (nvpltrlouu-uie modJ. Distillation, F:

IIlI 400 410 u. [)ry point. 4'15 1A IM n Flash point, F. (I t.'llSIy"\IU.I'LL'llS I60 AS'IM I) "3.

closed cup).

The amount of oil used in relation to the water to prepare the emulsion may be varied over wide ranges. As a general rule, the amount of oil-to'water may vary between 5:1-1210 with preferable emulsions being prepared in the ratio of 1:2 to 1:10. These ratios are illustrative of emulsions that can be prepared, although it should be understood that the invention is not limited thereby.

The emulsions may be prepared by any number of techniques. For example, the emulsions may be prepared by using high speed agitation or ultrasonic techniques. In most instances, however, it is desirable that the emulsion be a stable emulsion and to achieve this end it is often necessary to employ an oil-soluble emulsifying agent. The amount of emulsifying agent to provide an emulsion will have to be determined by routine experimentation. As a general rule it may be said that the amount of oil-soluble emulsifier may range from 0.1 to by weight based on the weight of the oil. To produce stable emulsions the amount of emulsifier will normally be within the range of 12-20% by weight of the oil.

Rather than provide a listing of suitable emulsifiers. we prefer to generally recommend as being satisfactory the so-called 10w HLB materials which are well documented in the literature and are summarized in the Atlas HLB Surfactant Selector. Although these emulsifiers are useful in producing good water-in-oil emulsions, other surfactants may be used as long as they are capable of producing these emulsions. For instance, We have found that certain high HLB surfactants are capable of producing stable water-in-oil emulsions. A typical low HLB emulsifier is sorbitan monooleate.

DISPERSING THE POLYMERS INTO THE WATER- IN-OIL EMULSIONS In accordance with the first step or procedure of the invention, the water-soluble vinyl addition polymers or the gums are dispersed into the water-in-oil emulsion. The polymers as produced by most manufacturing processes are in the form of powders or lump-like agglomerates of varying particle size. It is desirable that the particles, before being placed into the emulsion. be comminuted by grinding, abrading or the like so that their average particle size is less than 5 millimeters and preferably is within the range of l-5 microns. After the powders have been comminuted, they may be dispersed into the water-in-oil emulsion by means of agitation provided by such devices as stirrers, shakers, homogenizers and the like. To be commercially practical, the amount of polymer in the emulsion should be at least 2% by weight. The invention contemplates using emulsions containing between 575% by weight with preferred emulsions having a polymer concentration within the range of 10-45% by weight. In some cases the starting emulsions are converted to suspensions due to the nature and the amount of the polymer present therein.

The method of preparing a water-in-oil emulsion by the use of a homogenization device is quite simple. Water is added with agitation to an oil-emulsifier mixture to make tit) an emulsion. The finely divided polymer particles are then added to the emulsion with rapid agitation. The particle size of the polymer should be within the range of 1 micron to about 5 microns. This suspension of polymer particles in the emulsion is passed through a homogenizer. The amount of pressure necessary to produce a smooth emulsion varies in each experiment. The minimum pressure requirement is a function of the abrasiveness of the polymer, the concentration of the polymer, and the particle size of the polymer. In general, the pressure requirement is between 1000-3000 p.s.i. However, depending upon those variables listed. the pressure requirement could be lower or exceed the stated range. A typical homogenizer device is the Manton-Gaulin type.

From a commercial standpoint it is beneficial that the polymer emulsions thus described be stable, yet at the same time contain relatively large amounts of polymers. One method of insuring that the polymers do not precipi tate when dispersed in the emulsion is that the particle size of the polymer be as small as possible. Thus polymers dispersed in the emulsifiers are quite stable when the particle size is within the range of 5 millimicrons up to about 5 microns. To produce particle sizes within these limitations. spray dryers with appropriate size nozzles may be used. It also is possible to prepare the polymer-containing emulsion of the water-soluble vinyl addition polymers directly from the vinyl monomers from which these polymers are synthesized. Such polymer-containing emulsion may be synthesized by using the Water-in-oil-emulsion polymerization technique set forth in US. 3,284,393. The teachings of this patent comprise forming a water-in-oil emulsion of water-soluble ethylenic unsaturated monomers. The emulsion is formed by utilizing a water-in-oil emulsifying agent. To this monomer is added a free radical-type polymerization catalyst and then heat is applied under free radical-forming conditions to form water-soluble polymer latices. The polymeric latices produced by this patent are relatively unstable and frequently must be treated with additional emulsifiers to render the products stable.

INVERTING THE EMULSION The major discovery upon which this invention is predicated resides in the discovery that when the polymercontaining emulsions of the type described are inverted in the presence of water, that the polymer rapidly goes into solution. The polymer-containing emulsions release the polymer in the water in a very short period of time when compared to the amount of time required to dissolve a solid form of the polymer.

The polymer-containing emulsions may be inverted by any number of means. The most convenient means resides in the use of a surfactant added to either the polymercontaining emulsion or to the water into which it is to be dissolved. The placement of a surfactant into the water causes the emulsion to rapidly invert and release the polymer in the form of an aqueous solution. When this tech nique is used to invert the polymer-containing emulsion the amount of surfactant present in the water may vary over a range of 0.01 to based on polymer. Good inversion often occurs within the range of 1.0-10% based on polymer.

THE SURFACTANTS The preferred surfactants are hydrophilic and are further characterized as being water-soluble. Any hydrophilic-type surfactant such as ethoxylated nonyl phenols, ethoxylated nonyl phenol formaldehyde resin, dioctyl esters of sodium sulfosuccinate, and octyl phenol polyethoxy ethanol can be used.

Other surfactants that may be employed include the soaps such as sodium and potassium myristate, laurate, palmitate, oleate, stearate, resinate, and hydroabietate, the alkali metal alkyl or alkylene sulfates, such as sodium lauryl sulfate, potassium stearyl sulfate, the alkali metal alkyl or alkylene sulfonates, such as sodium lauryl sulfonate, potassium stearyl sulfonate, and sodium cetyl sulfonate, sulfonated mineral oil, as well as the ammonium salts thereof; and salts of high means like lauryl amine hydrochloride, and stearyl amine hydrobromide.

Following is a list of suitable surfactants that could be used in the practice of this invention. Any water-soluble surfactant could be used, but naturally some are more efficient than others. Useful surfactants include, but are not limited to: polyoxyethylene alkyl phenol, polyoxy- Any anionic, cationic, or nonionic compound can be ethylene mole) cetyl ether, polyoxyethylene alkylused as the surfactant. Examples of suitable anionic suraryl ether, polyoxyethylene monolaurate, polyoxyethylene factants are alkali metal, ammonium and amine soaps; vegetable oil, polyoxyethylene sorbitan monolaurate, polythe fatty acid part of such soaps contains preferably at oxyethylene esters or mixed fatty and resin acids, polyleast 16 carbon atoms because soaps based on lauric and 10 oxyethylene sorbitol lanolin dirivative, polyoxyethylene myristic acids have a great tendency to develop abundant (12 mole) tridecyl ether, polyoxyethylene sorbitan esters foamof mixed fatty and resin acids, polyoxyethylene sorbitan Other examples of suitable anionic surfactants are alkali monostearate, polyoxyethylene sorbitan monooleate, polymetal salts of alkyl-aryl sulfonic acids, sodium dialkyl oxyethylene monostearate, polyoxyethylene (20 mole) sulfosuccinate, sulfated or sulfonated oils, e.g., sulfated 15 stearyl ether, polyoxyethylene mole) oleyl ether, castor oil; sulfonated tallow, and alkali salts of short chain polyoxyethylene (15 mole) tridecyl ether, polyoxyethylpetroleum sulfonic acids. ene fatty alcohol, polyoxyethylene alkyl amine, polyoxy- Examples of suitable cationic surfactants are salts of ethylene glycol monopalmitate, polyoxyethylene sorbitan long chain primary, secondary, or tertiary amines, such as monopalmitate, polyoxyethylene (20 mole) cetyl ether, oleylamine acetate, cetyl'amine acetate, di-dodecylamine 2O polyoxyethylene oxypropylene stearate, polyoxyethylene lactate, the acetate of aminoethyl-aminoethyl stearamide, lauryl ether, polyoxyethylene lanolin derivative, sodium dilauroyl triethylene tetramine diacetate, 1-aminoethyl-2- oleate, quaternary ammonium derivative, potassium oleheptadecenyl imidazoline acetate; and quaternary salts, ate, N-cetyl N-ethyl morpholinium ethosulfate, and pure such as cetylpyridinium bromide, hexadecyl ethyl morsodium lauryl sulfate. pholinium chloride, and diethyl di-dodecyl ammonium 5 In addition to using the water-soluble surfactants dechloride. scribed above, other surfactants may be used such as sili- Examples of suitable nonionic surfactants are condencones, clays and the like which are included as surfactants sation products of higher fatty alcohols with ethylene oxsince, in certain instances, they tend to invert the emulsion ide, such as the reaction product of oleyl alcohol with 10 even though they are not water-soluble. ethylene oxide units; condensation products of alkyl- In other specific cases the surfactant may be directly phenols with ethylene oxide, such as the reaction products added to the polymer-containing emulsion; thereby renof isooctylphenol with 12 ethylene oxide units; condensadering it self-inverting upon contact with water. These tion products of higher fatty acid amides with 5, or more, products, while capable of being used in certain systems, ethylene oxide units; polyethylene glycol esters of long must be carefully formulated since the surfactants may chain fatty acids, such as tetraethylene glycol monopalmitend to interact with the emulsifier or the emulsion and tate, hexaethyleneglycol monolaurate, non-aethyleneglycol r y it prior to ts being used. monostearate, nonaethyleneglycol dioleate, tridecaethyl- Other techniques for inverting the emulsions include the eneglycol monoarachidate, tricosaethylene glycol monouse f agitation, g Voltage electrical fields, heat and behenate, tricosaethyleneglycol dibehenate, polyhydric P Shift, as Well as the Placement into the Water, into l h l i l hi h f tt i esters Such as sorbitan which the polymer-containing emulsion is to be dissolved, tristearate, ethylene oxide condensation products of polycertain elfich'olytes- For any Particular P y containing hydric alcohol partial higher fatty t d h i inner emulsion a suitable method for its inversion may be readanhydrides (mannitol-anhydride, called Mannitan, and ily determined by routine experimentation. sorbitol-anhydride, called Sorbitan), such as glycerol monopalmitate reacted with 10 molecules of ethylene EXAMPLES 23:2 g gi figz gg g g fif reactedtwltht 12 i To illustrate the invention the following presented exy S r 1 an [11.01195 eara e .reac e amples are set forth below in Table II. A variety of emulwith 10 to 15 molecules of ethylene oxide, long chain polyglycols in which one hydroxyl group is esterified with a prepared contammg fhfierent water.'solub1e higher fatty acid and the other hydroxy group is etherified vlriyl aqdltlon polymeirs' The emul.slons were then Inverted with a low molecular alcohol such as methoxypolyethyl using different techniques. Inversion Method l Io. l was ene glycol 550 monostearate (550 meaning tha average the placement of a surfactant into the water into which molecular Weight f the polyglycol ether) A combina the polymer was to be dissolved. Inversion Method No. 2 i of two or more f these f t t may be used; incorporated the surfactant into the emulsion. Inversion a cationic may be blended with a nonionic or an anionic Method 3 Was agitation Without the Presence of with a nonionic. surfactant.

TABLE II Water, Oil, Example percent percent Percentin Polymer particle, Inversion Dissolution number by wt by wt. Polymer emulsion size range method time 72 28 (I) 93% aerylamide; 7% methacrylic acid 35 5-70 microns 2 2 5 minutes. 72 28 (I) do 35 ...do 3 30-45nrinutes. 72 28 ('I) 35 -.do 2 5minutes. 72 28 (T) 35 ---..do 2 Do. 67 33 (I) 93% acrylamide; 7% methacrylic acid 32 30 microns 1 5-10 minutes. 67 33 (I) 75% acrylamide;25% DMAEM 30 do 1 Do. 67 33 (T) Acrylamide 35 10microns-1mm. 2 1 D0. 50 50 (I) acrylamide; 30% acrylic acid. 2 1 Immediate. 48 52 (1) Sodium polyacrylate 1 15 minutes. 23 67 (I) Acrylamide (dry solid nto emuls 1 1 hour. 42 58 (I) DMAEM 24 30 microns. 1 1 5 minutes. 42 58 (I) Polystyrene sulfonate 24 .d0 1 1 Do.

I Octyl phenol Rx with 3 moles of EtO. Octy phenol Rx with 10 moles of EtO. 3 Complex organic phosphate ester. No'rE.I=Isopar 3=Agitation without surfactant.

M; T=T0luene; DMAEM=Dimethy1 aminoethyl methacrylate. 1=Surfactant added to Water; 2=Surfactant added to emulsion;

7 EXAMPLE 13 Ten grams of polyethylene glycol dioleate were added with mixing to 30 grams of lsopar M. Fifty grams of water were added to the above mixture to make a smooth, water-in-oil emulsion.

Ten grams of a well ground finely-divided polyvinylalcohol, having a particle size between 1-5 microns, were added to the emulsion prepared above. This mixture was rapidly agitated for 5 minutes. At this time the mixture was passed through the Manton-Gaulin homogenizer. The pressure setting was 2000 p.s.i. The material passed through the device in 30 seconds. A second pass was also made at the same conditions. The resulting product was a smooth emulsion in which there was no visible settling out of polymer particles.

The material was inverted in water which contained 5% based on polymer of octyl phenol Rx with 10 moles of B as the surfactant. The polymer dissolved in water within 2 minutes.

Dry polymers corresponding to those shown in the examples without using the techniques of the invention take from 2 /2 to 10 hours to completely dissolve in water.

We claim:

1. A method of rapidly dissolving water-soluble vinyl addition polymers into water, which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein a finely-divided water-soluble vinyl addition polymer; thereby providing a polymer-containing emulsion; and then,

(B) inverting said emulsion in water whereby the water-soluble vinyl addition polymer is released into the water as a solution.

2. The method of claim 1 where the polymer-containing emulsion is inverted by means of agitation.

3. The method of claim 1 where the emulsion is inverted by means of a surfactant.

4. A method of rapidly dissolving water-soluble vinyl addition polymers into water, which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein at least 2% by weight of particles ranging in size from millimicrons to 5 millimeters of a water-soluble vinyl addition polymer; thereby providing a polymer-containing emulsion; and then,

(B) inverting said polymer-containing emulsion by adding it to water which contains from 0.01 to 50% by weight based on the weight of the polymer of a surfactant whereby the water-soluble vinyl addition polymer is released into the water as a solution.

5. The method of claim 4 where the surfactant is a water-soluble surfactant.

6. The method of claim 5 Where the surfactant is present in the water in an amount ranging from 1.0 to by weight.

7. A method of rapidly dissolving water-soluble vinyl addition polymers into water which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein from 5 to 75% by weight of par- 8 ticles ranging in size from 5 millimicrons to 5 microns of a water-soluble vinyl addition polymer; and then,

(B) inverting said polymer-containing emulsion by adding it in an amount to provide from 0.1 to 20% by weight of polymer to water which contains from 1.0 to 10% by weight of the polymer of a watersoluble surfactant whereby the water-soluble vinyl addition polymer is released into the water as a solution.

8. A method of rapidly dissolving water-soluble vinyl addition polymers into water, which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein a finely-divided water-soluble vinyl addition polymer and a compatible water-soluble surfactant, thereby providing a polymer-containing emulsion; and then,

(B) inverting said emulsion in water whereby the water-soluble vinyl addition polymer is released into the water as a solution.

9. The method of claim 8 where the polymer-containing emulsion is inverted by means of agitation.

10. A method of rapidly dissolving water-soluble vinyl addition polymers into water, which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein at least 2% by weight of particles ranging in size from 5 millimicrons to 5 millimeters of a water-soluble vinyl addition polymer and a compatible' water-soluble surfactant, thereby providing a polymer-containing emulsion; and then,

(B) inverting said emulsion in water whereby the water-soluble vinyl addition polymer is released into the water as a solution.

11. A method of rapidly dissolving water-soluble vinyl addition polymers into water which comprises the steps of:

(A) preparing a water-in-oil emulsion which contains dispersed therein from 5 to by weight of particles ranging in size from 5 millimicrons to 5 microns of a water-soluble vinyl addition polymer; and a compatible water-soluble surfactant, and then,

(B) inverting said emulsion in water whereby the Water-soluble vinyl addition polymer is released into the water as a solution.

12. The method of claim 1 where the water-soluble vinyl addition polymer is a polyacrylic acid.

13. The method of claim 8 where the water-soluble vinyl addition polymer is a polyacrylic acid.

References Cited UNITED STATES PATENTS 3,624,091 11/1971 Anderson et a1.

MELVIN GOLDSTElN, Primary Examiner US. Cl. X.R.

26029.6 H N, 29.6 B, 29.6 S Q UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,734,873

DA E I May 22, 1973 INVENTOR(S) 1 Donald R.- Anderson et a1.

It is certified that error appears in the above-identified patent and that saidLetters Patent are hereby corrected as shown below:

The term of this patent subsequent to November 30, 1988, has been disclaimed.

Signed and Scaled this Twelfth D of October 1976 [SEAL] Arrest:

RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioner uj'Palenls and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,734,873

D TE I May 22, 19.73

INVENTOR(S) Donald R. Anderson et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The term of this patent subsequent to November 30 1988, has been disclaimed.

Signed and Scaled this Twelfth D f October 1976 [SEAL] Arrest:

RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioner nj'latents and Trademarks 

